Novel light stabilizers

ABSTRACT

Novel compounds of the general formula I ##STR1## wherein M q ⊕ is a metal ion carrying a double or triple positive charge and q is 2 or 3 and r is 1 or 2, the quotient q/r being 1, 1.5, 2 or 3, and L is a piperidine which is substituted by at least one enolate group in the 1-position or 4-position and wherein the ring nitrogen is sterically hindered by alkyl substituents in the adjacent positions, and m is 0, 1 or 2 and A is H 2  O or an amine.

The present invention relates to novel compounds containing enol groups, their metal chelates, their preparation and their use as light stabilisers in organic material, and also to the organic material protected with the aid of these compounds.

Metal complexes with sterically hindered amines and anions carrying a single charge have been described as stabilisers for synthetic polymers in German Offenlegungschrift No. 2,625,967.

It is the object of the present invention to provide novel compounds containing enol groups, and their chelate complexes with metal cations carrying a double or triple charge, which are distinguished by a good light-stabilising action and good stability to extraction and have good compatibility in polymers.

The novel compounds have the general formula I ##STR2## in which M^(q)⊕ is a metal ion carrying a double or triple positive charge and q is 2 or 3 and r is 1 or 2, the quotient q/r being 1, 1.5, 2 or 3, and L is a piperidine which is substituted by at least one enolate group in the 1-position or 4-position and in which the ring nitrogen is sterically hindered by alkyl substituents in the adjacent positions, and m is 0, 1 or 2 and A is H₂ O or an amine.

The present invention relates in particular to compounds of the formula I in which M^(q)⊕ is a metal ion carrying a double or triple positive charge and q is 2 or 3 and r is 1 or 2, the quotient q/r being 1, 1.5, 2 or 3, and L is a group of the formula II ##STR3## in which R₁ is hydrogen or C₁ -C₄ alkyl and Z₁ is hydrogen, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl, C₃ -C₄ alkynyl, C₂ -C₂₁ alkoxyalkyl, C₇ -C₈ aralkyl, an aliphatic acyl group having 1-4 C atoms, or one of the groups --CH₂ COOR₂ or --CH₂ --CH(R₃)--OR₄, or a --(CH₂)₄ --R₅, --CH₂ --CH═CH--CH₂ --R₅, ##STR4## radical or a group of the formula III ##STR5## in which R₂ is C₁ -C₈ alkyl, C₃ -C₆ alkenyl, phenyl, C₇ -C₈ aralkyl or cyclohexyl and R₃ is hydrogen, methyl or phenyl and R₄ is an aliphatic C₁ -C₁₈ acyl group, an aromatic C₇ acyl group, an araliphatic C₈ -C₉ acyl group or an alicyclic C₆ -C₉ acyl group, in which the aromatic part can be unsubstituted or substituted by chlorine, C₁ -C₄ alkyl, C₁ -C₈ alkoxy, and/or hydroxyl, and R₅ is a group of the formula IV ##STR6## in which R₁, Z₂ and Z₃ are as defined below, and R₆ is a group of the formula V ##STR7## in which R₉ is hydrogen or C₁ -C₄ alkyl, and R₇ and R₈ independently of one another are hydrogen, methyl, phenyl, C₂ -C₉ alkoxymethyl or a --CH₂ --O--R₆ radical, in which R₆ is as defined above, and a is 0, 1 or 2 and b is 0 or 1 and c is 0 or, if a and/or b differ from 0, is also 1, and X and Y independently of each other are -O- or ##STR8## in which R₁₀ is hydrogen, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl, cyclohexyl, C₃ -C₂₁ alkoxyalkyl, C₇ -C₁₃ aralkyl, phenyl which is unsubstituted or substituted by C₁ -C₈ alkyl and/or C₁ -C₈ alkoxy, or a group --CH₂ --CH₂ --O--R₆, in which R₆ is as defined above, and R₁₀ is also a group of the formula VI ##STR9## in which R₁ is as defined above and R₁₁ is hydrogen, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl, C₂ -C₂₁ alkoxyalkyl, C₇ -C₈ aralkyl, an aliphatic acyl group having 1-4 C atoms, or a group --CH₂ COOR₂, in which R₂ is as defined above, and Z₂ is hydrogen, C₂ -C₁₈ aliphatic acyloxy, benzoyloxy which is unsubstituted or substituted by C₁ -C₈ alkyl or C₁ -C₈ alkoxy, or a C₂ -C₁₈ acylamido group which is unsubstituted or C₁ -C₈ N-alkyl-substituted, or one of the groups --R₁₂, --(CH₂)_(d) --R₁₂, ##STR10## in which d is 2 to 10 and R₁₂ is a group of the formula VII ##STR11## in which R₁ and Z₁ are as defined above, or Z₂ is also a group of the formula VIII ##STR12## in which R₁₂ is as defined above and X' is --O-- or ##STR13## in which R₁₄ is hydrogen or C₁ -C₄ alkyl, and R₁₃ is --(CH₂)_(e) -- or a group ##STR14## in which e is 0 to 8 and R₁₅ and R₁₆ independently of each other are hydrogen, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl, C₇ -C₁₁ aralkyl, cyanomethyl, cyanoethyl or a group --CH₂ COOR₁₇, in which R₁₇ is methyl or ethyl, or Z₂ is one of the groups ##STR15## in which R₆, R₇ and R₁₂ are as defined above and R₁₈ is hydrogen, C₁ -C₈ alkyl, allyl, phenyl or benzyl and R₁₉ is hydrogen, C₁ -C₈ alkyl, allyl or benzyl and R₂₀ is C₁ -C₄ alkyl or a group of the formula V which is as defined above, and R₂₁ is C₂ -C₆ alkylene, cyclohexylidene, phenylene, diphenylene, 4,4'-diphenylene oxide or 4,4'-diphenylenemethane, or Z₂ is also a group of the formulae XII, XIII or XIV ##STR16## in which a, b, c, X, Y, R₆, R₇ and R₈ are as defined above and f, a' and b' are 0 or 1 and g is 0 or, if a' and/or b' differ from 0, is also 1, and R₂₂ and R₂₃ independently of one another are hydrogen, C₁ -C₄ alkyl, cyclohexyl, phenyl, benzyl, α-methylbenzyl or α,α-dimethylbenzyl, and Z₃ is hydrogen or cyano, or Z₂ and Z₃ together are one of the groups XV, XVI or XVII ##STR17## in which R₆ is as defined above and R₂₄ is hydrogen, methyl or ethyl and R₂₅ is hydrogen, C₁ -C₁₈ alkyl, C₃ -C₈ alkenyl, cyclohexyl, C₇ -C₈ aralkyl or a group --CH₂ --COOR₂₆ or --CH₂ --CH(R₈)--O--R₆, in which R₂₆ is C₁ -C₁₈ alkyl and R₆ and R₈ are as defined above, and m is 0, 1 or 2 and A is H₂ O or an amine of the formula (XVIII) ##STR18## in which R₂₇ is substituted or unsubstituted alkyl, cycloalkyl, aryl or aralkyl, a substituted or unsubstituted aminoalkyl group or a piperidinyl group, and R₂₈ is hydrogen or substituted or unsubstituted alkyl or cycloalkyl, a substituted or unsubstituted aminoalkyl group or a substituted or unsubstituted piperidinyl group, or R₂₇ and R₂₈ together with the N atom form a pyrrolidine, piperidine or morpholine ring which is substituted by alkyl groups or is unsubstituted, and R₂₉ is hydrogen or substituted or unsubstituted alkyl.

A cation M of the valency q is, for example a cation of the series Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Zn²⁺, Cd²⁺, Al³⁺, Sn²⁺, Cr³⁺, Co²⁺ and Ni²⁺, an oxo complex of metal ions, especially VO²⁺ and MoO₂ ²⁺, or a tin-alkyl ion of the formula (R*)₂ Sn²⁺ or (CH₂ CH₂ COOR*)₂ Sn²⁺ in which R* is C₁ -C₈ alkyl, but especially ethyl, n-propyl and in particular n-butyl; preferred cations M^(q+) are especially Ca²⁺, Mg²⁺, Zn²⁺ and Co²⁺ and in particular Ni²⁺ or Al³⁺. The coordination numbers of these cations are known to those skilled in the art and are 4 or 6 depending on the metal.

q is 2 or 3, especially 2.

r is 1 or 2 and corresponds to the number of enolate anions in the ligand L. If the ligand L contains one enolate group, the complex as a rule contains q ligands L, unless a less than equivalent amount of L has been used for the preparation. If the ligand L contains two enolate groups, it is not necessary for the two enolic coordination positions to be occupied by one and the same metal centre M^(q+). Ligands L containing two enolate groups are therefore suitable for the preparation of oligomeric or even polymeric molecules, which are distinguished by an increased stability to extraction. The ratio of the metal M^(q+) to the ligand L^(r-) indicated in the formula I is also correct in this case if it is calculated for the structural unit on which the polymer is based. Such compounds are novel and have a molecular weight of about 400-10,000, preferably of 400-2,000.

As C₁ -C₄ alkyl, R₁ is branched or, especially, unbranched alkyl, such as ethyl, n-propyl or n-butyl, but in particular methyl. Preferably, R₁ is hydrogen. Preferably all the symbols R₁ have the same meaning.

As C₁ -C₁₂ alkyl, Z₁ is, for example, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-octyl, n-decyl or n-dodecyl. Preferred alkyl groups are those having 1-8 C atoms and especially those having 1-4 C atoms, and in particular methyl.

As C₃ -C₈ alkenyl, Z₁ is, for example, allyl, 2-butenyl, 2-hexenyl or 2-octenyl, especially allyl.

As C₃ -C₄ alkynyl, Z₁ is, for example, propargyl.

If Z₁ is C₂ -C₂₁ alkoxyalkyl, the alkyl moiety can contain 1-3 C atoms and the alkoxy moiety can consist of 1-18 C atoms, as, for example, in methoxymethyl, ethoxymethyl, 2-methoxyethyl, 2-ethoxyethyl, 2-n-butoxyethyl, 3-n-butoxyethyl, 2-octoxyethyl or 2-octadecyloxyethyl. Compounds to be mentioned in particular are those in which Z₁ is an alkoxyalkyl group having 2-6 C atoms.

As C₇ -C₈ aralkyl, Z₁ is, for example, benzyl or α-phenylethyl.

As an aliphatic acyl group having 1-4 C atoms, Z₁ is, for example, formyl, acetyl, acryloyl or crotonyl, especially acetyl.

If Z₁ is the group --CH₂ COOR₂, R₂, as C₁ -C₈ alkyl, is, for example, methyl, ethyl, isopropyl, n-butyl, isobutyl, t-butyl, isopentyl or n-octyl. Preferably, R₂ is C₁ -C₄ alkyl. As C₃ -C₆ alkenyl, R₂ is, for example, allyl, 2-butenyl or 2-hexenyl. As C₇ -C₈ aralkyl, R₂ is, for example, benzyl or α-phenylethyl.

If Z₁ is the group --CH₂ --CH(R₃)--OR₄, R₃ is hydrogen, methyl or phenyl, especially hydrogen. As an aliphatic C₁ -C₁₈ acyl radical, R₄ is, for example, formyl, acetyl, propionyl, butyryl, octanoyl, dodecanoyl, stearoyl or acryloyl. As an aromatic C₇ acyl radical, R₄ is benzoyl, and as an araliphatic C₈ -C₉ acyl radical, R₄ is cinnamoyl, phenylacetyl or phenylpropionyl. The aromatic part is unsubstituted or substituted by chlorine or C₁ -C₄ alkyl, such as methyl, ethyl, n-propyl or t-butyl, or by C₁ -C₈ alkoxy, such as methoxy, ethoxy, butoxy or octoxy, and/or hydroxyl. Substituted aromatic acyl groups are, for example, chlorobenzoyl, toluoyl, isopropylbenzoyl, 2,4-dichlorobenzoyl, 4-methoxybenzoyl, 3-butoxybenzoyl, 2-hydroxybenzoyl or 3,5-di-t.-butyl-4-hydroxybenzoyl. An araliphatic substituted acyl group is, for example, β-(3,5-di-t.-butyl-4-hydroxyphenyl)-propionyl. If R₄ is an alicyclic C₆ -C₉ acyl group, this can be cyclohexylcarbonyl or 2,4-dimethylcyclohexylcarbonyl.

If Z₁ is one of the groups --(CH₂)₄ --R₅, --CH₂ --CH═CH--CH₂ --R₅, ##STR19## the symbols R₁, Z₂ and Z₃ in these formulae are as defined. In formula IV, R₁ is most preferably hydrogen. Preferred compounds of the formula I are those in which all of the radicals R₁ in the molecule are identical. The same applies for all of the radicals Z₂ and all of the radicals Z₃.

If Z₁ is a group of the formula III, R₆ in this formula is a group of the formula V, in which R₉ is C₁ -C₄ alkyl, such as ethyl, propyl, n-butyl and especially methyl, and, most preferably, hydrogen.

As C₂ -C₉ alkoxymethyl, R₇ and R₈ are, for example, methoxymethyl, ethoxymethyl, propoxymethyl, butoxymethyl or octoxymethyl. The preferred meaning of R₇ and R₈ is hydrogen or methyl. Particularly interesting compounds are those in which R₇ is hydrogen and R₈ is hydrogen or methyl.

X is --O-- or ##STR20## preferably --O--.

Y is --O-- or ##STR21## preferably ##STR22## in which R₁₀ is most preferably hydrogen or also methyl.

As C₁ -C₁₂ alkyl, R₁₀ is, for example, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-octyl, n-decyl or n-dodecyl, but preferably methyl.

As C₃ -C₈ alkenyl, R₁₀ is, for example, allyl, 2-butenyl, 2-hexenyl or 2-octenyl, especially allyl.

If R₁₀ is C₃ -C₂₁ alkoxyalkyl, the alkyl moiety can contain, especially, 2-3 C atoms and the alkoxy moiety can consist of 1-18 C atoms, for example 2-methoxyethyl, 2-ethoxyethyl, 2-n-butoxyethyl, 3-n-butoxyethyl, 2-octoxyethyl or 2-octadecyloxyethyl.

As C₇ -C₁₃ aralkyl, R₁₀ is especially phenylethyl or in particular benzyl.

If R₁₀ is phenyl, it can be monosubstituted or disubstituted by C₁ -C₈ alkyl, such as methyl, ethyl, propyl, butyl, hexyl or octyl, especially methyl. As phenyl, R₁₀ can also be disubstituted, and preferably monosubstituted, by C₁ -C₈ alkoxy, such as methoxy, ethoxy, butoxy or octoxy, especially methoxy.

If R₁₀ is a group of the formula VI, R₁₁ in this formula, as C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl, C₂ -C₂₁ alkoxyalkyl or C₇ -C₈ aralkyl, or as an aliphatic acyl group having 1-4 C atoms or as the group --CH₂ COOR, can have the meaning indicated above by way of example for Z₁.

Z₂ can preferably be hydrogen.

If Z₂ is C₂ -C₁₈, preferably C₂ -C₁₂ and especially C₂ -C₇ aliphatic acyloxy, it can be acetyloxy, propionyloxy, butyryloxy, hexanoyloxy, heptanoyloxy, dodecanoyloxy or stearoyloxy.

As benzoyloxy, Z₂ can be disubstituted, and preferably monosubstituted, by C₁ -C₈ alkyl, such as methyl, ethyl, propyl, butyl or octyl, especially by methyl, or by C₁ -C₈ alkoxy, such as methoxy, ethoxy, butoxy or octoxy, especially by methoxy; particularly interesting compounds are those in which Z₂, as benzoyloxy, is unsubstituted.

As C₂ -C₁₈ acylamido, Z₂ is, for example, acetylamido, propionylamido, butyrylamido, hexanoylamido, heptanoylamido, dodecanoylamido or stearoylamido. Acylamido groups having 2-12 C atoms, and especially those having 2-7 C atoms, are preferred.

If Z₂ is a C₁ -C₈ N-alkyl-substituted C₂ -C₁₈ acylamido group, possible N-alkyl substituents are, for example, methyl, ethyl, n-propyl, n-butyl, n-hexyl or n-octyl.

If Z₂ contains a radical R₁₂, this radical can be linked to the piperidine ring directly or preferably via an alkylene group having 2-10 C atoms and preferably 2-6 C atoms, such as dimethylene, trimethylene, tetramethylene, hexamethylene or decamethylene. Linkages via a xylylene or bitolylene bridge are equally preferred as alkylene bridges.

Z₂ can be a group of the formula VIII in which R₁₃, as alkylene, can have, for example, 1-8 and preferably 1-6 C atoms, such as methylene, dimethylene, trimethylene, tetramethylene, hexamethylene or octamethylene. The index e can, however, just as preferably be 0, i.e. the alkylene group can also be omitted.

X' is --O-- or ##STR23## in which R₁₄, as C₁ -C₄ alkyl, is ethyl, propyl or butyl, and the preferred meaning of R₁₄ is hydrogen or methyl.

R₁₃ can also be a group --(R₁₅)C(R₁₆)--, in which R₁₅ and R₁₆ can be C₁ -C₁₂, and preferably C₁ -C₄, alkyl, such as methyl, ethyl, propyl, butyl, hexyl, octyl or dodecyl.

As C₃ -C₈ alkenyl, R₁₅ and R₁₆ are, for example, allyl, 2-butenyl, 2-hexenyl or 2-octenyl, especially allyl.

As C₇ -C₁₁ aralkyl, R₁₅ and R₁₆ are especially phenylethyl or in particular benzyl.

R₁₅ and R₁₆ can be cyanoethyl and especially also cyanomethyl.

In the groups of the formulae IX or X, R₁₈, as C₁ -C₈ alkyl, can be, for example, methyl, ethyl, propyl, butyl, hexyl or octyl. Preferably, however, R₁₈ is hydrogen.

In formula X, R₁₉, as C₁ -C₈ alkyl and preferably C₁ -C₄ alkyl, can be, for example, methyl, ethyl, n-propyl, n-butyl, hexyl or octyl. R₁₉ is also preferably hydrogen, allyl or benzyl.

In formula XI, R₂₀, as C₁ -C₄ alkyl is, for example, methyl, ethyl, n-propyl or n-butyl. A preferred meaning of R₂₀ to be mentioned is, however, a group of the formula V.

In the formula XI, R₂₁ is most preferably C₂ -C₆ alkylene, such as dimethylene, trimethylene, tetramethylene or hexamethylene. However, it can also preferably be cyclohexylidene or phenylene.

If Z₂ is a group of the formula XII, the indices a', b' and g in this formula are preferably 0.

In the formulae XIII and XIV, R₂₂ and R₂₃, as C₁ -C₄ alkyl, can be, for example, methyl, ethyl, propyl or butyl; ethyl and especially methyl are preferred, as is also hydrogen.

If Z₂ and Z₃ together form a heterocyclic structure, groups of the formula XV and XVI are particularly preferred.

R₂₄ is then ethyl, preferably methyl and especially hydrogen.

As C₁ -C₁₂ alkyl, R₂₅ is, for example, methyl, ethyl, propyl, butyl, hexyl, octyl, decyl or dodecyl. Alkyl groups having 1-8 C atoms are preferred.

As aralkyl having 7-8 C atoms, R₂₅ is in particular phenylethyl or especially benzyl.

As C₃ -C₈ alkenyl, R₂₅ is, for example, allyl, 2-butenyl, 2-hexenyl or 2-octenyl, especially allyl.

As C₁ -C₁₈ alkyl, R₂₆ is, for example, methyl, ethyl, propyl, butyl, hexyl, octyl, dodecyl or octadecyl. Preferred alkyl radicals are those having 1-12 and especially 1-8 C atoms and in particular those having 1-4 C atoms.

If A is an amine of the formula XVIII, the substituents R₂₇, R₂₈ and R₂₉ thereof are, for example, C₁ -C₁₈ alkyl, such as methyl, ethyl, isopropyl, sec.-butyl, n-hexyl, n-octyl, n-decyl, n-dodecyl or n-octadecyl, most preferably C₁ -C₈ alkyl.

If the said alkyl is substituted alkyl, it is in particular C₁ -C₁₈ hydroxyalkyl, such as 1-hydroxyethyl, 1-hydroxypropyl, 1-hydroxy-1-methylethyl, 3-hydroxy-pentyl or 1-hydroxy-2-methyl-ethyl, preferably C₁ -C₈ hydroxyalkyl.

R₂₇ and R₂₈ can also be C₅ -C₁₂, and especially C₅ -C₆ cycloalkyl, for example, cyclopentyl, cyclohexyl, 4-methylcyclohexyl or 4-tert.-butyl-cyclohexyl. R₂₇ can also be substituted or unsubstituted C₆ -C₁₀ aryl, for example phenyl, tolyl, xylyl, tert.-butyl-phenyl or dodecylphenyl. As C₇ -C₂₀ aralkyl, R₂₇ is, for example, benzyl, 4-methylbenzyl, 4-t.-butylbenzyl or 4-dodecylbenzyl, especially benzyl.

A substituted or unsubstituted aminoalkyl group represented by R₂₇ and R₂₈ is in particular an aminoalkyl group substituted by a piperidinyl group, for example an aminoalkyl group of the formula VIIb ##STR24## in which R₁, R₁₁ and R₁₄ are as defined above and v is an integer from 1 to 8.

A substituted or unsubstituted piperidinyl group represented by R₂₇ and R₂₈ is preferably a piperidinyl grup of the formula VI.

R₂₇ and R₂₈ together with the N atom of the amine of the formula XVIII can form a pyrrolidine, piperidine or morpholine ring which is substituted by alkyl groups or is unsubstituted. In this case, the ring can be, for example, a 2,5-dimethylpyrrolidine, 4-methylpiperidine, 2,2,6,6-tetramethylpiperidine, 2,6-dimethylmorpholine, pyrrolidine, piperidine or morpholine ring, especially a 2,2,6,6-tetramethylpiperidine ring.

m can be 0, 1 or 2, preferably 0.

Thus, when the ligand A is an amine it is, as defined herein, a primary, secondary or tertiary amine which is able to form a complex with the metal chelates listed above. Examples of such amines are: n-butylamine, n-dodecylamine, β-ethylhexylamine, benzylamine, 4-octylbenzylamine, dibutylamine, dicyclohexylamine, dioctadecylamine, morpholine, 2,2,6,6-tetramethylpiperidine, N-ethylaniline, tri-n-octylamine, N,N-dimethylaniline, N,N-dimethyl-cyclohexylamine, N-ethylpiperidine, N-methylpyrrolidine, dibenzylpropylamine, N-benzyl-2,5-dimethylpyrrolidine, 4-dimethylamino-2,2,6,6-tetramethylpiperidine, 4-dimethylamino-1,2,2,6,6-pentamethylpiperidine, N,N'-methyl-N,N'-(1,2,2,6,6-pentamethyl-4-piperidyl)-ethylenediamine, hydroxyethylamine, di-(hydroxyethyl)-amine, tri-(hydroxyethyl)-amine, tri-(2-hydroxypropyl)-amine, N-phenyl-N,N-di-(hydroxyethyl)-amine or hydroxy-propylamine.

The complexes according to the invention, of the formula I, contain, per mol of metal M^(q) ⊕, 0 to 2 mols of the amine ligand A, all or part of which can be replaced by water. The molar proportion expressed by m in the formula I is thus made up of the sum of m' mols of the amine ligand and m" mols of water; the molar proportions expressed by m' and m" do not need to be an integer. Preferred complexes are those which have a low water content since these dissolve in non-polar polymers better than do highly hydrated complexes. m' thus assumes approximately the value of m.

An amine ligand A is necessary only when the coordination number of the metal centre is not satisfied by the chelate-forming agent L alone.

Preferred compounds of the formula I are those in which M^(q)⊕ is Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Zn²⁺, Cd²⁺, Al³⁺, Sn²⁺, Cr³⁺, Co²⁺, Ni²⁺, VO²⁺, MoO²⁺, (R*)₂ Sn²⁺ or (CH₂ CH₂ COOR*)₂ Sn²⁺, in which R* is C₁ -C₈ alkyl and q is 2 or 3 and r is 1 or 2, the quotient q/r being 1, 1.5, 2 or 3, and L is a group of the formula II, in which R₁ is hydrogen or methyl and Z₁ is hydrogen, C₁ -C₈ alkyl, C₃ -C₄ alkenyl, C₃ alkynyl, C₂ -C₁₀ alkoxyalkyl, C₇ -C₈ aralkyl, acetyl or one of the groups --CH₂ COOR₂ or --CH.sub. 2 --CH(R₃)--OR₄, or a --(CH₂)_(4--R) ₅, --CH₂ --CH═CH--CH₂ --R₅, ##STR25## radical or a group of the formula III, in which R₂ is C₁ -C₄ alkyl, C₃ -C₄ alkenyl, phenyl, C₇ -C₈ aralkyl or cyclohexyl and R₃ is hydrogen or methyl, R₄ is an aliphatic acyl group having 1-12 atoms and R₅ is a group of the formula IV, in which Z₂ and Z₃ are as defined below and R₁ is hydrogen, and R₆ is a group of the formula V, in which R₉ is hydrogen or methyl, and R₇ and R₈ independently of one another are hydrogen or methyl and a is 0, 1 or 2 and b is 0 or 1 and c is 0 or, if a and/or b differ from 0, is also 1, and X is --O-- and Y is --O-- or ##STR26## in which R₁₀ is hydrogen or methyl or, if a, b and c are 1, R₇ is hydrogen and Y is --O--, also a group --CH₂ --CH₂ --OR₆, in which R₆ is as defined above, and Z₂ is hydrogen, C₂ -C₁₂ aliphatic acyloxy, benzoyloxy which is unsubstituted or monosubstituted or disubstituted by methyl or methoxy, or a C₂ -C₁₂ acylamido group which is unsubstituted or C₁ -C₄ N-alkylsubstituted, or one of the groups --R₁₂, --(CH₂)_(d) --R₁₂, ##STR27## in which d is 2 to 16 and R₁₂ is a group of the formula VII, in which R₁ and Z₁ are as defined above, or Z₂ is also a group of the formula VIII, in which X' is --O-- or ##STR28## in which R₁₄ is hydrogen or C₁ -C₄ alkyl, and R₁₃ is --(CH₂)_(e) or a group ##STR29## in which e is 0 to 8 and R₁₅ and R₁₆ independently of one another are hydrogen, C₁ -C₄ alkyl, allyl, benzyl, cyanomethyl, cyanoethyl or a group --CH₂ COOR₁₇, in which R₁₇ is methyl or ethyl, or Z₂ is a group of the formulae IX, X or XI, in which R₆ and R₇ are as defined above, R₁₈ is hydrogen, R₁₉ is hydrogen, C₁ -C₄ alkyl, allyl or benzyl, R₂₀ is C₁ -C₄ alkyl or a group of the formula V, which is as defined above, and R₂₁ is C₂ -C₆ alkylene, cyclohexylidene or phenylene, or Z₂ is also a group of the formula XIIa ##STR30## in which a, b, c, R₆ and R₇ are as defined above and f is 0 or 1 and X₁ is --O-- or ##STR31## in which R₁₀ * is hydrogen, C₁ -C₁₂ alkyl, cyclohexyl, C₃ -C₁₄ alkoxyalkyl, C₇ -C₈ aralkyl, phenyl which is unsubstituted or monosubstituted or disubstituted by C₁ -C₃ alkyl and/or C₁ -C₈ alkoxy, or, if a, b and c are 1, R₇ is hydrogen and Y is --O--, also a group --CH₂ --CH₂ --OR₆, in which R₆ is as defined above, and R₁₀ * is also a group VI, in which R₁ is as defined above and R₁₁ is hydrogen, methyl or allyl, and Y₁ is --O-- or ##STR32## in which R₁₀ * is hydrogen, C₁ -C₈ alkyl or phenyl, or Z₂ is also one of the groups XIII or XIV, in which R₆ is as defined above and R₂₂ and R₂₃ independently of one another are hydrogen, methyl or ethyl, and Z₃ is hydrogen or cyano, or Z₂ and Z₃ together are one of the formulae XV, XVI or XVII, in which R₆ is as defined above and R₂₄ is hydrogen, methyl or ethyl and R₂₅ is hydrogen, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl or a group --CH₂ COOR₂₆ or --CH₂ --CH(R₈)--OR₆, in which R₆ and R₈ are as defined above and R₂₆ is C₁ -C₁₂ alkyl, and m is 0, 1 or 2 and A is H₂ O or an amine of the formula XVIII, in which R₂₇ is unsubstituted or --OH-substituted C₁ -C₁₈ alkyl, C₅ -C₁₂ cycloalkyl, unsubstituted or C₁ -C₁₂ alkylsubstituted C₆ -C₁₀ aryl or C₇ -C₂₀ aralkyl, a substituted or unsubstituted aminoalkyl group having 1-8 C atoms in the alkyl part, or a piperidinyl group, and R₂₈ is hydrogen or unsubstituted or --OH-substituted C₁ -C₁₈ alkyl, C₅ -C₁₂ cycloalkyl or a substituted or unsubstituted aminoalkyl group having 1-8 C atoms in the alkyl part, or a piperidinyl group, or R₂₇ and R₂₈ together with the N atom form a pyrrolidine, piperidine or morpholine ring which is substituted by alkyl groups or is unsubstituted, and R₂₉ is hydrogen or unsubstituted or --OH-- substituted C₁ -C₁₈ alkyl.

Particularly preferred compounds are those of the formula I in which M^(q)⊕ is Ca²⁺, Mg²⁺, Zn²⁺, Co²⁺, Ni²⁺ or Al³⁺ q is 2 or 3 and r is 1 or 2, the quotient q/r being 1, 1.5, 2 or 3, L is a group of the formula II, in which R₁ is hydrogen or methyl and Z₁ is hydrogen, C₁ -C₄ alkyl, allyl, C₂ -C₆ alkoxyalkyl, benzyl, acetyl or one of the groups --CH₂ COOR₂ or --CH₂ --CH(R₃)--OR₄ or a group of the formula III, in which R₂ is C₁ -C₄ alkyl and R₃ is hydrogen and R₄ is an aliphatic acyl group having 1-8 C atoms and R₆ is a group of the formula V, in which R₉ is hydrogen, and R₇ is hydrogen and R₈ is hydrogen or methyl and a is 0, 1 or 2 and b is 0 or 1 and c is 0 or, if a and/or b differ from 0, is also 1, and X is --O-- and Y is --O-- or ##STR33## in which R₁₀ is hydrogen or methyl or, if a, b and c are 1 and Y is --O--, also a group --CH₂ --CH₂ --OR₆, in which R₆ is as defined above, and Z₂ is hydrogen, C₂ -C₇ aliphatic acyloxy, benzoyloxy which is unsubstituted or monosubstituted by methyl or methoxy, or a C₂ -C₇ acylamido group which is unsubstituted or N-substituted by methyl, or one of the groups ##STR34## in which d is 2 to 6 and R₁₂ is a group of the formula VII, in which R₁ and Z₁ are as defined above, or Z₂ is also a group of the formula VIII, in which X' is --O-- or ##STR35## in which R₁₄ is hydrogen or methyl, and R₁₃ is --(CH₂)_(e) -- or a group ##STR36## in which e is 0 to 8 and R₁₅ and R₁₆ independently of one another are hydrogen, C₁ -C₄ alkyl, allyl, benzyl or cyanomethyl, or Z₂ is also a group of the formula XI, in which R₂₀ is a group of the formula V, which is as defined above, and R₂₁ is C₂ -C₆ alkylene or phenylene, or Z₂ is also a group of the formula XXIa, in which a, b, c, R₆ and R₇ are as defined above and f is 0 or 1 and X₁ is --O-- or ##STR37## in which R₁₀ * is hydrogen, C₁ -C₈ alkyl, cyclohexyl, C₃ -C₈ alkoxyalkyl, C₇ -C₈ aralkyl, phenyl which is unsubstituted or monosubstituted by C₁ -C₃ alkyl and/or C₁ -C₂ alkoxy, or, if a, b and c are 1 and Y₁ is --O-- also a group --CH₂ --CH₂ --OR₆, in which R₆ is as defined above, and R₁₀ * is also a group VI, in which R₁ is as defined above and R₁₁ is hydrogen or methyl, and Y₁ is --O-- or ##STR38## in which R₁₀ * is hydrogen, C₁ -C₄ alkyl or phenyl, or Z₂ is also one of the groups XIII or XIV, in which R₆ is as defined above and R₂₂ and R₂₃ independently of one another are hydrogen, methyl or ethyl, and Z₃ is hydrogen, or Z₂ and Z₃ together are one of the formulae XV, XVI or XVII, in which R₆ is as defined above and R₂₄ is hydrogen or methyl and R₂₅ is C₁ -C₈ alkyl, allyl or one of the groups --CH₂ --COOR₂₆ or --CH₂ --CH(R₈)--OR₆, in which R₆ and R₈ are as defined above, and R₂₆ is C₁ -C₈ alkyl, and m is 0, 1 or 2, and A is H₂ O or an amine of the formula XVIII, in which R₂₇ and R₂₈ independently of one another are C₁ - C₈ alkyl, C₁ -C₆ hydroxyalkyl or a substituted aminoalkyl group of the formula VIIb ##STR39## in which R₁, R₁₁ and R₁₄ are as defined above and v is 1 to 8, or R₂₇ and R₂₈ together with the N atom form a piperidine group, and R₂₉ is hydrogen, C₁ -C₈ alkyl or C₁ -C₆ hydroxyalkyl.

Compounds of particular interest are those of the formula I, in which M^(q)⊕ is Ca²⁺, Mg²⁺, Zn²⁺, Co²⁺, Ni²⁺ or Al³⁺ and q is 2 or 3 and r is 1 or 2, the quotient q/r being 1, 1.5, 2 or 3, and L is a group of the formula II, in which R₁ is hydrogen and Z₁ is hydrogen, methyl, acetyl or a group of the formula III, in which R₆ is a group of the formula V, in which R₉ is hydrogen, and R₇ is hydrogen and R₈ is hydrogen or methyl, and a is 0, 1 or 2 and b is 0 or 1 and c is 0 or, if a and/or b differ from 0, is also 1, X is --O-- and Y is ##STR40## in which R₁₀ is hydrogen, and Z₂ is hydrogen, C₂ -C₇ aliphatic acyloxy, benzoyloxy, an acylamido group which is unsubstituted or N-substituted by methyl, or one of the groups --(CH₂)_(d) --R₁₂, ##STR41## in which d is 2 to 6 and R₁₂ is a group of the formula VII, in which R₁ and Z₁ are as defined above, or Z₂ is also a group of the formula VIII, in which X' is --O-- or ##STR42## in which R₁₄ is hydrogen or methyl, and R₁₃ is --(CH₂)_(e) -- or a group ##STR43## in which e is 0 to 8 and R₁₅ and R₁₆ independently of one another are hydrogen, C₁ -C₄ alkyl, allyl or benzyl, or Z₂ is also a group of the formula XI, in which R₂₀ is a group of the formula V, which is as defined above, and R₂₁ is C₂ -C₆ alkylene, or Z₂ is also a group of the formula XIIa, in which a, b, c, R₆ and R₈ are as defined above and f is 0 or 1 and X₁ is --O-- or ##STR44## in which R₁₀ * is hydrogen, C₁ -C₈ alkyl, C₃ -C₆ alkoxyalkyl, C₇ -C₈ aralkyl, phenyl which is unsubstituted or monosubstituted by methyl, methoxy or ethoxy, or a group VI, in which R₁ is as defined above and R₁₁ is hydrogen or methyl, and Y₁ is --O--, or Z₂ is also one of the groups XIII or XIV, in which R₆ is as defined above and R₂₂ and R₂₃ independently of one another are hydrogen or methyl, and Z₃ is hydrogen, or Z₂ and Z₃ together are one of the formulae XV, XVI or XVII, in which R₆ is as defined above and R₂₄ is hydrogen and R₂₅ is C₁ -C₈ alkyl or one of the groups --CH₂ COOR₂₆ or --CH₂ --CH(R₈)--OR₆, in which R₆ and R₈ are as defined above, and R₂₆ is C₁ -C₄ alkyl, and m is 0, 1 or 2, and A is H₂ O or an amine of the formula XVIII, in which R₂₇ and R₂₈ independently of one another are C₁ -C₈ alkyl, C₁ -C₆ hydroxyalkyl or a group VIIb, in which R₁, R₁₁ and R₁₄ are as defined and v is 1 to 8, or R₂₇ and R₂₈ together with the N atom form a piperidine group, and R₂₉ is hydrogen, C₁ -C₈ alkyl or C₁ -C₆ hydroxyalkyl.

Examples of compounds of the formula I are metal complexes of a metal M^(q)⊕ with one of the following ligands: 2,3,6-trimethyl-2,6-diethyl-4-(1',3'-dioxobutyloxy)-piperidine, 2,2,6,6-tetramethyl-4-(1',3'-dioxopentyloxy)-piperidine, 1-{2"-[N-n-butyl-N-(1',3'-dioxobutyl)]-amino-2"-methylethyl}2,2,6,6-tetramethyl-4-heptanoyloxy-piperidine, 1-[(2'-phenyl-3',6'-dioxa-5'-methyl-7',9'-dioxo)-decyl]-2,2,6,6-tetramethylpiperidine, N,N-dimethyl-N,N'-bis-[1-(3'-oxa-4',6'-dioxo)-heptyl-2,2,6,6-tetramethyl-piperidin-4-yl]-hexamethylenediamine, bis-[1-(3'-oxa-4',6'-dioxo)-heptyl-2,2,6,6-tetramethyl-piperidin-4-yl]-p-xylidene, bis-[1-(3'-oxa-4',6'-dioxo)-heptyl-2,2,6,6-tetramethyl-piperidin-4-yl]adipate, bis-[1-(3'-oxa-4',6'-dioxo)-heptyl-2,2,6,6-tetramethyl-piperidin-4-yl]-n-butyl malonate, bis-[1-(3'-oxa-4',6'-dioxo)-heptyl-2,2,6,6-tetramethyl-piperidin-4-yl]methyl-carbethoxymethyl malonate, 3-n-octyl-7,7,9,9-tetramethyl-8-[(3'-oxa-4',6'-dioxo)-heptyl]-1,3,8-triazaspiro-[4,5]-decane-2,4-dione, 1,2,2,6,6-pentamethyl-4-[1',4',8'-trioxa-9',11'-dioxo-6'-(1",3"-dioxobutyloxy)]-piperidine, 2,2,6,6-tetramethyl-4-[4'-(1",3"-dioxobutyloxy)-3'-t.butyl-phenyl]-piperidine, 2,2,6,6-tetramethyl-4-[3',5'-dimethyl-4'-(1",3"-dioxo-butyloxy)-cyclohexyl]-piperidine, 3-ethyl-3-(1',3'-dioxo-butyloxy-methyl)-8,8,10,10-tetramethyl-1,5-dioxa-9-aza-spiro[5,5]-undecane, 3-(2'-methyl-3'-oxa-4',6'-dioxo-heptyl)-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4,5]-decane-2,4-dione, bis-(2,2,6,6-tetramethyl-piperidin-4-yl)-[2'-methoxymethyl-3'-oxa-4',6'-dioxoheptyl] malonate, bis-(2,2,6,6-tetramethyl-piperidin-4-yl)-methyl-]N-benzyl-N-(1',3'-dioxo-butyl)-aminopropyl] malonate and 2,2,6,6-tetramethyl-4-cyano-4-(1',3'-dioxo-butyloxy)-piperidine.

The ligands listed here can be converted into metal complexes with a metal M^(q)⊕ by one of the processes described below.

The compounds according to the invention are distinguished by the fact that the ligands L, complexed therein, contain at least one radical R₆, which is as defined above. The ligands of the formula II used for the synthesis are novel, with the exception of 2,2,6,6-tetramethyl-4-piperidinyl acetoacetate, which also falls under general formula II, and are therefore also a subject of the present invention. The ligands of the formula II can be prepared in a known manner from the analogous compounds of the formula II', in which the substituent R₆ in the radicals Z₁ and Z₂ had been replaced by hydrogen and all the other symbols are as defined for formula II. In particular, the procedure is that the corresponding hydroxy derivatives or amino derivatives are reacted direct or in a solvent with a diketene corresponding to the formula V or with a diketene homologue, the addition of a catalyst usually being unnecessary (c.f. Houben-Weyl "Methoden der organischen Chemie" ("Methods of organic chemistry"), 4th edition, volume 7/4, page 226 et seq.). The diketene is preferably employed in a stoichiometrically equivalent amount or in an excess of up to 10%. Suitable solvents for these reactions are, especially, benzene, toluene, dioxane, dichloroethane, pyridine or dimethylformamide. On the other hand, however, these compounds can be obtained from the intermediates of the formula II', described by the above definition, and β-ketocarboxylates by trans-esterification, or by aminolysis of carboxylates, in a manner which is known per se.

Those intermediates (of the general formula II') in which geminal hydroxyl groups occur can be obtained from 2,2,6,6-tetraalkylpiperidine derivatives which contain primary or secondary amino groups or primary hydroxyl groups and 2,3-epoxy-1-propanol by the known methods for epoxide conversions.

The starting materials of the formula II' are known or, if they are novel, can be prepared according to methods which are known per se and analogously to known compounds. Thus, for example, 4-aminopiperidine derivatives are important starting materials which can be prepared by the processes described in German Offenlegungsschrift No. 2,040,975 or German Offenlegungsschrift No. 2,349,962. Those piperidine derivatives which are substituted on the 4-amino group by an alkylamino group can be prepared in an analogous manner by using a piperidin-4-one derivative as the starting material and reacting this with a monoalkylated diamine.

The piperidine derivatives which contain an alkoxyamino group, especially the oxypropylamino group) in the 4-position are prepared from the corresponding 4-hydroxypiperidine derivatives, which are added onto acrylonitrile by methods which are known per se; the cyano group is then hydrogenated to the corresponding primary amine. Further important starting materials for the preparation of compounds according to formula I are those compounds which at the same time carry a cyano group and a hydroxyl group in the 4-position of the piperidine ring (cyanohydrins), or at the same time carry a cyano group and an amino group in the 4-position of the piperidine ring. The preparation of these compounds is described in U.S. Pat. No. 3,513,170. Hydrogenation of these nitriles then gives, in a known manner, the corresponding 4-methylamino derivatives. α-Aminocarboxylates, the α-carbon atom of which is in the 4-position in the piperidine derivatives which can be used, are also starting materials for the preparation of compounds of the formula I which are claimed.

The free acids can be prepared from the corresponding piperidin-4-one derivatives by the method of H. T. Bucherer (J. prakt. Chem. 140, 291 (1934)) via hydantoins as intermediates and with subsequent alkaline saponification. Conversion to the corresponding esters is effected in a manner which is known per se with the aid of an acid catalyst.

As described in British Pat. No. 1,337,600, the piperidin-4-one derivatives substituted on the nitrogen in the 1-position can be obtained by protecting the keto group by converting it into a ketal. After introducing the substituent in the 1-position by the conventional methods, the protective group is detached again in a known manner.

The metal complexes of the compounds of the formula I are prepared in a manner which is known per se, for example by dissolving the β-keto-esters or β-keto-amides of the formula II in a non-aqueous solvent, preferably a lower alcohol (especially ethanol) and adding an alkali metal alcoholate in an amount equivalent to the enolisable keto groups. The number of mols of a dissolved metal salt necessary to give a molar ratio between the metal ion of valency q⁺ and the neutralised enolate groups of the ligand molecule of r/q are then added slowly. Solvents which can be used for the metal salt are, in particular, the solvent used initially, or a solvent miscible therewith. The reaction mixture is then stirred at a temperature between 30° and 100° C. for about 1 hour. Metal salts which can be used are, preferably, those which have anions which give sparingly soluble precipitates with the alkali metal ions in the chosen solvents. Precipitation usually takes place on the addition of the metal salt or on subsequent stirring or heating of the reaction mixture. In these cases, the alkali metal salts can be separated off by filtration. Alternatively, they can frequently be separated off after evaporation of the solvent or by extraction of the metal compound with a non-polar solvent. Metal salts which can be used are, especially, chlorides, such as nickel chloride, cobalt-II chloride or dibutyl-tin dichloride. If the salts used are not anhydrous or if the solvents used contain water, the latter can be incorporated into the complex which forms, either as water itself or, alternatively, in the deprotonated form as the hydroxyl ion. In these cases, the end products frequently also contain the alkali metal which was used in the form of an alcoholate in order to form the enolate groups. If the metal salt used is a salt of a carboxylic acid (for example the nickel salt of 2-ethylcaproic acid), the carboxylate ion can frequently not be separated off as the alkali metal salt, or can be only partially separated off as the alkali metal salt, because it is incorporated into the complex as a further ligand anion, in addition to the enolate ions.

Metal alkoxides (for example aluminium triisopropylate) can also be used in place of inorganic metal salts and metal carboxylates as reactants for the formation of metal complexes of a compound of the formula I. In these cases, neutralisation of the β-keto ester or β-keto amide with an alkali metal alcoholate is omitted.

If the metal complexes of the compounds of the formula I contain an amine as a further ligand, this can already be added before the alkali metal alcoholate is added, or the metal complex obtained in the manner described above can be dissolved in a solvent containing the amine and this solvent can then be removed again by evaporation.

If the procedure described is followed for the preparation of metal complexes of the compounds of the formula I, mixtures of different complexes, in particular those in which the ratio of the metal ion to the ligand L is greater than r/q, frequently form. These mixtures can also be used as effective stabilisers, like the single compounds of this formula.

According to the present invention, the compounds of the formula I can be used as stabilisers for plastics in order to protect them against damage by the action of oxygen, heat and light. Examples of such plastics are the polymers listed on pages 12-14 of German Offenlegungsschrift No. 2,456,864.

The stabilising of polyolefines, styrene polymers and polyamides and of polyurethanes is of particular importance, and the compounds of the formula I are outstandingly suitable for this. Examples of such polymers are high density and low density polyethylene, polypropylene, ethylene/propylene copolymers, polystyrene, styrene/butadiene/acrylonitrile tercopolymers, mixtures of polyolefines or of styrene polymers, and polyurethanes based on polyethers or polyesters, in the form of lacquers, filaments, films, elastomers or foams.

The stabilisers are added to the plastics in a concentration of 0.01 to 5% by weight, calculated relative to the material to be stabilised. Preferably, 0.03 to 1.5, and particularly preferentially 0.15 to 0.6, % by weight of the compounds, calculated relative to the material to be stabilised, are incorporated into the latter.

Incorporation can be effected after polymerisation, for example by mixing the compounds and, if desired, further additives into the melt by the methods customary in the art, before or during shaping, or by applying the dissolved or dispersed compounds to the polymer, with subsequent evaporation of the solvent if necessary.

The novel compounds can also be added to the plastics to be stabilised in the form of a master batch which contains these compounds, for example in a concentration of 2.5 to 25% by weight.

In the case of crosslinked polyethylene, the compounds are added prior to crosslinking.

The invention therefore also relates to the plastics stabilised by the addition of 0.01 to 5% by weight of a compound of the formula I, which plastics can, if desired, contain yet further known and customary additives. The plastics stabilised in this way can be employed in very diverse forms, for example as films, fibres, tapes or profiles or as binders for lacquers, adhesives or putties.

Examples which may be mentioned of further additives, together with which the stabilisers which can be used according to the invention can be employed, are: antioxidants, such as simple 2,6-dialkylphenols, derivatives of alkylated hydroquinones, hydroxylated thiodiphenyl ethers, alkylidene-bisphenols, O-, N- and S-benzyl compounds, hydroxybenzylated malonates, hydroxybenzyl-aromatic compounds, s-triazine compounds, amides of β-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionic acid, esters of β-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionic acid, esters of β-(5-tert.-butyl-4-hydroxy-3-methylphenyl)-propionic acid, esters of 3,5-di-tert.-butyl-4-hydroxyphenylacetic acid, acylaminophenols, benzylphosphonates, aminoaryl derivatives, UV absorbers and light stabilisers, such as 2-(2'-hydroxyphenyl)-benztriazoles, 2,4-bis-(2'-hydroxyphenyl)-6-alkyl-s-triazines, 2-hydroxybenzophenones and 1,3-bis-(2'-hydroxybenzoyl)-benzenes, esters of substituted or unsubstituted benzoic acids, acrylates and, furthermore, nickel compounds, sterically hindered amines, oxalic acid diamides, metal deactivators, phosphites, compounds which destroy peroxide, polyamide stabilisers, basic Co stabilisers, PVC stabilisers, nucleating agents or other additives, for example plasticisers, lubricants, emulsifiers, fillers, carbon black, asbestos, kaolin, talc, glass fibres, pigments, optical brighteners, flameproofing agents and antistatic agents.

Examples of further additives together with which the stabilisers which can be used according to the invention can be employed are given on pages 18-24 of German Offenlegungsschrift No. 2,427,853.

The preparation and use of the compounds according to the invention is described in more detail in the examples which follow. The temperature data always relate to ° C.

EXAMPLES 1 TO 10

The compounds of Examples 1-10 were prepared according to the following general instructions (see Table 1).

0.1 mol of the compounds indicated in column 2 was dissolved in 100 ml of benzene and the amount of diketene (β-methylene-β-propiolactone) indicated in column 3, which was mixed with benzene in a ratio of 1:1, was added dropwise in the course of 30 minutes. The temperature of the reaction mixture was not more than 60°. The mixture was then warmed at 60° for 4 hours and the solvent was then evaporated. The residue was worked up by the method described in column 4. The end product indicated in column 5 had the properties indicated in column 6.

                                      TABLE 1                                      __________________________________________________________________________     1.     2.       3.     4.       5.          6.                                                 Number                                                                         of mols                                                        Ex-             of                                                             ample                                                                              Starting material                                                                          diketene                                                                            Working up                                                                             End product  Properties                           __________________________________________________________________________     1   1-(2'-hydroxyethyl)-                                                                       0.103                                                                               distillation                                                                           1-[2'-(1",3"-dioxo-                                                                         boiling point                            2,2,6,6-tetramethyl-     butoxy)-ethyl]-                                                                             140-142°/                         piperidine               2,2,6,6-tetramethyl-                                                                        1.5 mm Hg                                                         piperidine                                        2   1-(2'-hydroxyethyl)-                                                                       0.210                                                                               molecular                                                                              1-[2'-(1",3"-dioxo-                                                                         fraction vola-                           2,2,6,6-tetramethyl-                                                                            distillation                                                                           butoxy)-ethyl]-4-                                                                           tile at 55°                       4-hydroxy-piperidine                                                                            under a high                                                                           (1",3"-dioxobutoxy)-                                                                        and 0.01 mm                                               vacuum  2,2,6,6-tetramethyl-                                                                        Hg.                                                               piperidine   Elementary                                                                     analysis:                                                                      found C 61.78%                                                                 H 8.35% N 3.74%                                                                calculated                                                                     C 61.77%                                                                       H 8.46%                                                                        N 3.79%                              3   2,2,6,6-tetramethyl-                                                                       0.103                                                                               distillation                                                                           2,2,6,6-tetramethyl-4-                                                                      boiling point                            4-hydroxy-piperidine     (1',3'-dioxobutoxy)-                                                                        126-127°/                                                  piperidine   1.5 mm Hg                            4   1,2,2,6,6-penta-                                                                           0.103                                                                               distillation                                                                           1,2,2,6,6-penta-                                                                            boiling point                            methyl-4-hydroxy-        methyl-4-(1',3'-dioxo-                                                                      114-115°/                         piperidine               butoxy)-piperidine                                                                          0.7 mm Hg                            5   2,2,6,6-tetramethyl-                                                                       0.103                                                                               distillation                                                                           2,2,6,6-tetramethyl-4-                                                                      boiling point                            4-(N-n-butylamino)-      [N-n-butylamine-N-                                                                          187°/0.8 mm Hg                    piperidine               (1',3'-dioxobutyl)]-                                                           piperidine                                        6   1,2,2,6,6-penta-                                                                           0.103                                                                               distillation                                                                           1,2,2,6,6-penta-                                                                            boiling point                            methyl-N-(N-n-           methyl-4-[N-n-                                                                              180-181°/0.9 mm Hg                heptylamino)-            heptylamino-N-(1',3'-                                 piperidine               dioxobutyl)]-                                                                  piperidine                                        7   2,2,6,6-tetramethyl-                                                                       0.103                                                                               molecular                                                                              2,2,6,6-tetramethyl-4-                                                                      fraction volatile                        4-[N-n-heptyl-N-(2'-                                                                            distillation                                                                           N-n-heptyl-N-[2'-(1",                                                                       at 75° and 0.01 mm                hydroxyethyl)-amino]-                                                                           under a high                                                                           3"-dioxobutoxy)-                                                                            Hg. Elementary                           piperidine       vacuum  ethyl]-piperidine                                                                           analysis:                                                                      found C 69.9%                                                                  H 11.2% N 7.4%                                                                 calculated C 69.65%                                                            H 11.18% N 7.06%                     8   2-hydroxymethyl-7,7,                                                                       0.103                                                                               distillation                                                                           2-(1',3'-dioxobutoxy-                                                                       boiling point                            9,9-tetramethyl-1,4-     methyl)-7,7,9,9-tetra-                                                                      136°/0.3 mm Hg                    dioxy-8-azaspiro[4.5]    methyl-1,4-dioxa-8-                                   decane                   azaspiro[4.5]-decane                              9   N,N'-bis-(2,2,6,6-                                                                         0.210                                                                               recrystallisa-                                                                         N,N'-bis-(1',3'-dioxo-                                                                      melting point 171°                tetramethyl-4-   tion from                                                                              butyl-N,N'-bis-                                       piperidyl)-      ethylene                                                                               (2,2,6,6-tetramethyl-                                 ethylenediamine  glycol  4-piperidyl)-                                                          dimethyl ether                                                                         ethylenediamine                                   10  1-(2',3'-dihydroxy-                                                                        0.210                                                                               recrystallisa-                                                                         1-[2',3'-bis-(1",3"-                                                                        melting point                            propyl)-2,2,6,6- tion from                                                                              dioxobutoxy)-propyl]-                                                                       78-80°                            tetramethyl-     light benzine                                                                          2,2,6,6-tetramethyl-                                  piperidine       (boiling point                                                                         piperidine                                                             110-130°)                                          11  1-(2'-hydroxypropyl)-                                                                      1.05 distillation                                                                           1-[2'-(1",3"-dioxo-                                                                         boiling point                            2,2,6,6-tetramethyl-     butyloxy)-propyl]-2,2,                                                                      136-137°/0.8 mmHg                 piperidine               6,6-tetramethyl-                                                               piperidine                                        12  2,2,6,6-tetramethyl-                                                                       1.05 distillation                                                                           2,2,6,6-tetramethyl-4-                                                                      boiling point                            4-(N-ethylamino)-        [N-ethylamino-N-(1',3'-                                                                     117-118°/0.1 mmHg                 piperidine               dioxobutyl)]-piperidine                           13  1-allyl-2,2,6,6-                                                                           1.05 distillation                                                                           1-allyl-2,2,6,6-tetra-                                                                      boiling point                            tetramethyl-4-           methyl-4-(1',3'-dioxo-                                                                      136-137°/0.8 mmHg                 hydroxy-piperidine       butoxy)-piperidine                                                                          found C 68.5%                                                                  H 9.8%a N 5.0%                                                                 calculated C 68.29%                                                            H 9.67% N 4.98%                      14  1-n-butyl-2,2,6,                                                                           1.05 distillation                                                                           1-n-butyl-2,2,6,6-                                                                          boiling point                            6-tetramethyl-4-         tetramethyl-4-(1',3'-                                                                       147-148°/1.0 mmHg                 hydroxy-piperidine       dioxobutoxy)-                                                                               found C 68.9%                                                     piperidine   H 10.5% N 4.8%                                                                 calculated C 68.88%                                                            H 10.20% N 4.73%                     15  1,4-bis(2',2',6',                                                                          2.10 recrystall-                                                                            1,4-bis[2',2',6',6'-                                                                        melting point                            6'-tetramethyl-4'-                                                                              isation from                                                                           tetramethyl-4'-(1",                                                                         126-128°                          hydroxy-piperidino)-                                                                            ether   3"(-dioxobutoxy)-                                                                           found C 67.4%                            butene(2)                piperidino]-butene(2)                                                                       H 9.3% N 5.5%                                                                  calculated C 67.38%                                                            H 9.43% N 5.24%                      16  bis-[1-(2'-hydroxy-                                                                        2.10 recrystall-                                                                            bis[1-(3'-oxa-4',6'-                                                                        melting point                            ethyl)-2,2,6,6-  isation from                                                                           dioxo-heptyl)-2,2,6,                                                                        124-125°                          tetramethyl-piper-                                                                              acetonitrile                                                                           6-tetramethyl-                                        idin-4-yl]-tereph-       piperidin-4-yl]-                                      thalate                  terephthalate                                     __________________________________________________________________________

EXAMPLES 17 TO 26

The compounds of Examples 17-26 (see Table 2) were prepared according to the following general instructions.

0.1 mol of the compounds indicated in column 2 was dissolved in 200 ml of methanol and 100 ml of a 1.0 molar solution of sodium methylate in methanol were added. 0.05 mol of the metal salts indicated in column 3, dissolved in 160 ml of methanol, was added dropwise to the solutions in the course of 30 minutes. The reaction mixture was then refluxed for 30 minutes and the neutral salt which had precipitated out was separated off by filtration. In Example 14 the reaction mixture was not heated after addition of the metal salt and a neutral salt did not separate out. The resulting solutions were evaporated to dryness and the residue was eluted with the extraction agent indicated in column 4. The extract was evaporated and the residue was dried for 10 hours at a temperature of 60° (exception: Example 14: 40°) and under a pressure of 11 mm Hg. The solid end products indicated in column 5 were obtained in this way and the properties of these products are indicated in column 6.

                                      TABLE 2                                      __________________________________________________________________________     1.  2.      3.       4.      5.                  6.                                Starting                                                                       materials                                                                      compounds                                                                      according                                                                  Ex  to             Extraction                 Properties                       ample                                                                              Example                                                                              Metal salts                                                                             agent  End products        Colour                           __________________________________________________________________________     17  1     NiCl.sub.2                                                                              methylene                                                                             1:2 Ni chelate of 1-[2',                                                                           light                                                                              Ni content 9.4%                                 chloride                                                                              1",3"-dioxobutoxy)- green                                                      ethyl]-2,2,6,6-tetra-   N content 3.75%                                        methylpiperidine                                                               enolate                                              18  3     NiCl.sub.2                                                                              chloroform                                                                            1:2 Ni chelate of 2,2,6,                                                                           light                                                                              Ni content 10.1%                                       6-tetramethyl-4-(1',3'-                                                                            green                                                      dioxobutoxy)-piperidine N content 5.1%                                         enolate                                              19  4     NiCl.sub.2                                                                              methylene                                                                             1:2 Ni chelate of   light                                                                              Ni content 9.9%                                 chloride                                                                              1,2,2,6,6-penta-    green                                                      methyl-4-(1',3'-dioxo-  N content 4.95%                                 butoxy)-piperidine                                                                    enolate                                              20  4     Mg (CH.sub.3 COO.sup.-).sub.2                                                           methylene                                                                             1:2 Mg-II chelate of                                                                               white                                                                              melting point 221-                              chloride                                                                              1,2,2,6,6-penta-        225°                            4 H.sub.2 O     methyl-4-(1',3'-dioxo-  content of elements                                    butoxy)-piperidine      in %                                                   enolate containing13/4  found                                                  mols of H.sub.2 O per .sub.Mg +2                                                                       C 59.62% H 9.08%                                                               Mg 4.03%                                                                       calculated C 59.57%                                                            H 9.19% Mg 4.30%             21  5     ZnCl.sub.2                                                                              hexane 1:2 Zn-II chelate of 2,2,6,6-                                                                      white                                                                              Zn content 10.0%                                       tetramethyl-4-[N-n-butylamine-N-                                               (1',3'-dioxobutyl]-piperidine                                                                          N content 8.5%                                         enolate                                              22  6     NiCl.sub.2                                                                              hexane 1:2 Ni-chelate of 1,2,2,6,6-                                                                       light                                                                              Ni content 7.5%                                        pentamethyl-4-[N-n-heptyl-                                                                         green                                                      amino-N-(1',3'-dioxobutyl)]-                                                                           N content 7.6%                                         piperidine enolate                                   23  8     NiCl.sub.2                                                                              ether  1:2 Ni chelate of 2-(1',3'-dioxo-                                                                  light                                                                              Ni content 8.1%                                        butoxymethyl)-7,7,9,9-tetramethyl-                                                                 green                                                      1,4-dioxy-8-azaspiro[4.5]-decane                                                                       N content 4.25%                                        enolate                                              24  10    NiCl.sub.2                                                                              ether  1:2-Ni-chelate of the 1-[2'-(1",                                                                   light green                                                3"-dioxobutyloxy)propyl]-2,2,6,6-                                                                  Ni content 9.8%                                            tetramethylpiperidine enolate                                                                      N content 4.4%                   25  11    NiCl.sub.2                                                                              hexane 1:2 Ni-chelate of the 2,2,6,6-                                                                     light green                                                tetramethyl-4[N-ethylamino-N-                                                                      Ni content 8.5%                                            (1',3'-dioxobutyl)]-piperidine                                                                     N content 9.1%                                             enolate                                              26  12    NiCl.sub.2                                                                              hexane 1:2 Ni-chelate of the 1-allyl-                                                                     light green                                                2,2,6,6-tetramethyl-4-(1',3'-                                                                      Ni content 8.7%                                            dioxobutoxy)-piperidine                                                                            N content 4.5%                                             enolate                                              __________________________________________________________________________

EXAMPLE 27

18.5 g (0.05 mol) of 1-[2'-(1",3"-dioxobutoxy)-ethyl]-4-(1",3"-dioxobutoxy)-2,2,6,6-tetramethylpiperidine were dissolved in 200 ml of methanol and 5.40 g (0.1 mol) of sodium methylate were added.

16.3 g (0.05 mol) of nickel-II oenenthate (which contained 1/2 mol of water per mol), dissolved in 330 ml of benzene, were added dropwise to this solution in the course of 30 minutes. The mixture was stirred at room temperature for 4 hours and clarified by filtration and the filtrate was evaporated to dryness. The residue was washed with water and dried for 18 hours at a temperature of 60° and under a pressure of 11 mm Hg, affording the 1:1 nickel-II complex of 1-[2'-(1",3"-dioxobutoxy)-ethyl]-4-(1",3"-dioxobutoxy)-2,2,6,6-tetramethylpiperidine dienolate as a monohydrate in the form of a yellowish-green powder.

Elementary analysis: Found: C 51.40%; H 7.22%; N 2.92%; Ni 13.0%; Calculated for the monohydrate: C 51.37%; H 7.02%; N 3.15%; Ni 13.2%.

EXAMPLE 28

25.3 g (0.05 mol) of N,N'-bis-(1',3'-dioxobutyl)-N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-ethylenediamine were dissolved in 500 ml of toluene and 76.9 ml of a 1.3 molar sodium methylate solution (0.1 mol) were added. 16.3 g (0.05 mol) of nickel-II oenanthate (which contained 1/2 mol of water per mol), dissolved in 330 ml of toluene, were then added dropwise under reflux and the reaction mixture was refluxed for 15 minutes. The precipitated sodium oenanthalate was filtered off and the filtrate was evaporated to dryness. The residue was extracted with toluene at room temperature and the extract was evaporated in vacuo. The resulting residue was dried for 10 hours at a temperature of 60° and under a pressure of 11 mm Hg, affording the 1:1 nickel complex of N,N'-bis-(1',3'-dioxobutyl)-N,N'-bis-(2,2,6,6-tetramethyl-4-piperidyl)-ethylenediamine dienol in the form of a light green powder which contains 9.4% of nickel and 9.2% of nitrogen and in which oenanthic acid anions have been coordinatively incorporated, in addition to the said ligand.

EXAMPLE 29

12.1 g (0.05 mole) of 2,2,6,6-tetramethyl-4-(1',3'-dioxobutoxy)-piperidine are dissolved in 400 ml of ethanol and 3.40 g (0.166 mole) of aluminium isopropylate are added. The mixture is heated, giving a clear solution which is refluxed for two hours. The solvent and the liberated isopropanol are evaporated off and the product is dried at a temperature of 60° C. and under a pressure of 11 mm Hg, affording the 1:3 aluminium (II) complex of the 2,2,6,6-tetramethyl-4-(1',3'-dioxybutoxy)-piperidine enolate in the form of a white powder.

Elementary analysis: Found: C 62.33%; H 9.03%; N 5.64%; Al 3.73%; Calculated: C 62.63%; H 8.89%; N 5.62%; Al 3.61%.

EXAMPLE 30 Light protective action in polypropylene fibres

1000 parts of unstabilised polypropylene powder (melt index˜18) are mixed in a drum mixer with 1 part of pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and with 3 parts of the additives listed in the table. The mixture is then extruded in an extruder at 220° C. and granulated. The resulting granulate is spun to a 130/37 denier monofilament in a laboratory melt spinning machine at a maximum temperature of 270° C. and a speed of 300 m/minute. This monofilament is drawn and twisted in a draw twister. The draw ratio is 1:5.6 and the twist count is 15/meter, so that finally multifilaments of 130/37 denier are obtained. These multifilaments are mounted on white cardboard and exposed in a xenotest 1200.

The exposure time until 50% loss of ultimate tensile strength is taken as index of the protective action. The results are reported in Table 3.

                  TABLE 3                                                          ______________________________________                                                    Time taken until the ultimate                                                  tensile strength has been reduced                                              to half of the initial value                                                   through exposure in a xenotest                                      Additive   1200                                                                ______________________________________                                         none              35 hours                                                     compound 19      2050 hours                                                    ______________________________________                                    

EXAMPLE 31 Light protective action in high pressure polyethylene sheets

100 parts of low density polyethylene granulate (0.917) and 0.05 part of a stabiliser of the following table are homogenised for 10 minutes at 180° C. in a Brabender plastograph. The resulting mass is removed from the kneader as quickly as possible and pressed to a sheet having a thickness of 2 to 3 mm in a toggle press. A portion of this sheet is cut out and pressed between two high-gloss rigid aluminium sheets with a hand-operated hydrolic laboratory press for 6 minutes at 170° C. and under a pressure of 12 tons to a sheet having a thickness of 0.1 mm which is immediately chilled in water. Sections each measuring 60×44 mm are then punched out of this sheet and exposed in a xenotest 1200. These blanks are taken out of the exposure apparatus at regular intervals and tested for their carbonyl content in an IR spectrophotometer. The increase of the carbonyl extinction during the exposure is an index of the photooxidative degradation of the polymer (see L. Blavan et al; J. Polymer Sci., Part C, 22, 1059-1071 (1969); J. F. Heacock, J. Polymer Sci., Part A-1, 22, 2921-34 (1969); D. J. Carlsson and D. M. Wiles, Macromolecules 2, 587-606 (1969) and, as previous experience has shown, is allied to a decrease in the mechanical properties of the polymer.

The time taken until a carbonyl extinction of 0.100 is attained serves as index of the protective action.

The results are reported in Table 4.

                  TABLE 4                                                          ______________________________________                                                        Exposure time in a xenotest                                                    1200 until a carbonyl extinction                                Additive       of 0.1 has been detected                                        ______________________________________                                         none             270 hours                                                     compound 17     800 hours                                                       20            1840 hours                                                       22            2300 hours                                                      ______________________________________                                    

EXAMPLE 32 Light protection of polyethylene blown films

100 parts of low density polyethylene (melt index 0.1-0.3 g/10 min, 190° C., 2.16 kg) were mixed for 2 minutes in a cooled intensive mixer (marketed by Henschel) with one of the additives listed in Table 5 and 0.03 part of 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)octadecylpropionate. The mixture was extruded from a single screw extruder having a diameter of 35 mm and a length of 700 mm, in the process of which the temperature was adjusted in the first section to 190° C. and in the following three sections to 200° C., then chilled in water and granulated. This granulate was pressed at 190° C. through a blown film extruder having a diameter of 60 mm and a length of 1200 mm. At the exit of the extruder was a tubular die having a diameter of 120 mm and which was adjusted to a temperature of 200° C. The tubular film blown from the extruder was inflated in the ratio of 1:1.8. The rate of discharge was 5 m/min. The sheets had a thickness of 0.2 mm. These sheets were exposed in a xenotest 1200 exposure apparatus.

The carbonyl extinction of the sheets was measured at regular intervals in an infra-red spectrophotometer. The oxidation caused by the carbonyl extinction corresponds in the range of 0.1 to a mechanical damage of the sheet which indicates the onset of unfitness for use. The exposure time until the sheet has attained the carbonyl extinction of 0.1 referred to above is reported in Table 5 and serves as index of the stabilisation.

                  TABLE 5                                                          ______________________________________                                                       Exposure time in a xenotest 1200                                               until a carbonyl extinction of 0.1                               Additive      has been attained                                                ______________________________________                                         none           320 hours                                                       compound 19   3650 hours                                                       ______________________________________                                    

EXAMPLE 33 Stabilisation of polypropylene against light

100 parts of polypropylene powder (Moplen, fibre grade, marketed by Montedison), 0.2 part of β-(3,5-di-tert-butyl-4-hydroxyphenyl)octadecylpropionate and 0.25 part of a stabiliser of the following table are homogenised for 10 minutes at 200° C. in a Brabender plastograph. The resulting mass is removed from the kneader as quickly as possible and pressed to a sheet having a thickness of 2 to 3 mm in a toggle press. A portion of this sheet is cut out and pressed between two high-gloss aluminium sheets with a hand-operated hydraulic laboratory press for 6 minutes at 260° C. and under a pressure of 12 tons to a sheet having a thickness of 0.1 mm which is immediately chilled in water. Sections each measuring 60×44 mm are then punched out of this sheet and exposed in a xenotest 1500. These blanks are taken out of the exposure apparatus at regular intervals and tested for their carbonyl content in an IR spectrophotometer. The increase of the carbonyl extinction at 5.85μ during the exposure is an index of the photooxidative degradation of the polymer (see L. Blaban et al., J. Polymer Sci, Part C; 22, 1059-1071 (1969) and, as previous experience has shown, is allied to a decrease in the mechanical properties of the polymer.

The time taken until a carbonyl extinction of about 0.3 is attained, at which the comparison sheet is brittle, serves as index of the protective action.

The protective action of the stabilisers of the invention is evident from the following table:

    ______________________________________                                                      Exposure time in a xenotest 150 until                                          a carbonyl extinction of 0.3 has been                             Additive     detected                                                          ______________________________________                                         none         1050                                                              compound 1   3300                                                              compound 4   3900                                                              ______________________________________                                    

Polypropylene ribbons

1000 parts of polypropylene powder (melt index 1.5 g/10 minutes at 230° C., 2160 g) are mixed in a drum mixer with 1 part of pentaerythritol tetrakis-[3-(3',5'-di-tert-butyl-4-hydroxyphenyl)-propionate] and 2.5 parts the additives listed in the following table and subsequently extruded in an extruder at a temperature of 200°-220° and granulated. The resultant granulate is processed to a sheet in the conventional manner using an extruder with slot die. This sheet is cut into ribbons which are then stretched to 6 times their length at elevated temperature. The titre of the ribbons is 700-900 den., and their ultimate tensile strength is 5.5-6.5 g/den.

These ribbons are then exposed in a xenotest 1200. Samples are subjected at regular intervals to a tensile elongation test, in the course of which a progressive decrease in the ultimate tensile strength results with increasing exposure. The exposure time until the ultimate tensile strength has fallen to half the initial value is prolonged by the action of the light stabilisers.

    ______________________________________                                                      Exposure time in a xenotest 1200                                               until the ultimate tensile strength                                            has been reduced to half the initial                              Additive     value                                                             ______________________________________                                         none          400                                                              compound 9   4000        hours                                                  17          2800        hours                                                  18          >5000       hours                                                  19          3250        hours                                                  21           825        hours                                                  22          3000        hours                                                  28          2400        hours                                                  29          >3500       hours                                                 ______________________________________                                     

What is claimed is:
 1. A compound of formula I ##STR45## wherein M^(q) ⊕ is a metal ion carrying a double or triple positive charge and q is 2 or 3 and r is 1 or 2, the quotient q/r being 1, 1.5, 2 or 3, and L is a piperdine, which is substituted by at least one enolate group in the 1-position or 4-position and wherein the ring nitrogen is sterically hindered by alkyl substituents in the adjacent positions, having the formula II ##STR46## in which R₁ is hydrogen or C₁ -C₄ alkyl and Z₁ is hydrogen, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl, C₃ -C₄ alkynyl, C₂ -C₂₁ alkoxyalkyl, C₇ -C₈ aralkyl, an aliphatic acyl group having 1-4 C atoms, or one of the groups --CH₂ COOR₂ or --CH₂ --CH(R₃)--OR₄, or a --(CH₂)₄ --R₅, --CH₂ --CH═CH--CH₂ --R₅, ##STR47## radical or a group of the formula III ##STR48## in which R₂ is C₁ -C₈ alkyl, C₃ -C₆ alkenyl, phenyl, C₇ -C₈ aralkyl or cyclohexyl and R₃ is hydrogen, methyl or phenyl and R₄ is an aliphatic C₁ -C₁₈ acyl group, an aromatic C₇ acyl group, an araliphatic C₈ -C₉ acyl group or an alicyclic C₆ -C₉ acyl group, in which the aromatic part can be unsubstituted or substituted by chlorine, C₁ -C₄ alkyl, C₁ -C₈ alkoxy and/or hydroxy, and R₅ is a group of the formula IV ##STR49## in which Z₂ and Z₃ are as defined below, and R₆ is a group of the formula V ##STR50## in which R₉ is hydrogen or C₁ -C₄ alkyl, and R₇ and R₈ independently of each other are hydrogen, methyl, phenyl, C₂ -C₉ alkoxymethyl or a --CH₂ --O--R₆ radical, in which R₆ is as defined above, and a is 0, 1 or 2 and b is 0 or 1 and c is 0 or, if a and/or b differ from 0, is also 1, and X and Y independently of each other are --O-- or ##STR51## in which R₁₀ is hydrogen, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl, cyclohexyl, C₃ -C₂₁ alkoxyalkyl, C₇ -C₁₃ aralkyl, phenyl which is unsubstituted or substituted by C₁ -C₈ alkyl and/or C₁ -C₈ alkoxy, or a group --CH₂ --CH₂ --O--R₆, in which R₆ is as defined above, and Z₂ is hydrogen, C₂ -C₁₈ aliphatic acyloxy, benzoyloxy which is unsubstituted or substituted by C₁ -C₈ alkyl or C₁ -C₈ alkoxy, or C₂ -C₁₈ acylamido group which is unsubstituted or C₁ -C₈ N-alkylsubstituted, or one of the groups --R₁₂, --(CH₂)_(d) --R₁₂, ##STR52## in which d is 2 to 10 and R₁₂ is a group of the formula VII ##STR53## in which R₁ and Z₁ are as defined above, or Z₂ is also a group of the formula VIII ##STR54## in which R₁₂ is as defined above and X' is --O-- or ##STR55## in which R₁₄ is hydrogen or C₁ -C₄ alkyl, and R₁₃ is --(CH₂)_(e) -- or a group ##STR56## in which e is 0 to 8 and R₁₅ and R₁₆ independently of one another are hydrogen, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl, C₇ -C₁₁ aralkyl, cyanomethyl, cyanoethyl or a group --CH₂ COOR₁₇, in which R₁₇ is methyl or ethyl, or Z₂ is one of the groups ##STR57## in which R₆, R₇ and R₁₂ are as defined above and R₁₈ is hydrogen, C₁ -C₈ alkyl, allyl, phenyl or benzyl and R₁₉ is hydrogen, C₁ -C₈ alkyl, allyl or benzyl and R₂₀ is C₁ -C₄ alkyl or a group of the formula V which is as defined above, and R₂₁ is C₂ -C₆ alkylene, cyclohexylidene, phenylene, diphenylene, 4,4'-diphenylene oxide or 4,4'-diphenylenemethane, or Z₂ is also a group of the formulae XII, XIII or XIV ##STR58## in which a, b, c, X, Y, R₆, R₇ and R₈ are as defined above and f, a' and b' are 0 or 1 and g is 0 or, if a' and/or b' differ from 0, is also 1, and R₂₂ and R₂₃ independently of one another are hydrogen, C₁ -C₄ alkyl, cyclohexyl, phenyl, benzyl, α-methylbenzyl or α,α-dimethylbenzyl, and Z₃ is hydrogen or cyano, or Z₂ and Z₃ together are one of the groups XV, XVI or XVII ##STR59## in which R₆ is as defined above and R₂₄ is hydrogen, methyl or ethyl and R₂₅ is hydrogen, C₁ -C₁₈ alkyl, C₃ -C₈ alkenyl, cyclohexyl, C₇ -C₈ aralkyl or a group --CH₂ --COOR₂₆ or --CH₂ --CH(R₈)--O--R₆, in which R₂₆ is C₁ -C₁₈ alkyl and R₆ and R₈ are as defined above, and m is 0, 1 or 2 and A is H₂ O or an amine of the formula (XVIII) ##STR60## in which R₂₇ is substituted or unsubstituted alkyl, cycloalkyl, aryl or aralkyl, a substituted or unsubstituted aminoalkyl or piperidinyl group, and R₂₈ is hydrogen or substituted or unsubstituted alkyl or cycloalkyl, a substituted or unsubstituted aminoalkyl group or a piperidinyl group, or R₂₇ and R₂₈ together with the N atom form a pyrrolidine, piperidine or morpholine ring which is substituted by alkyl groups or is unsubstituted, and R₂₉ is hydrogen or substituted or unsubstituted alkyl.
 2. A compound according to claim 1 of the formula I, wherein M^(q)⊕ is Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Zn²⁺, Cd²⁺, Al³⁺, Sn²⁺, Cr³⁺, Co²⁺, Ni²⁺, VO²⁺, MoO²⁺, (R*)₂ Sn²⁺ or (CH₂ CH₂ COOR*)₂ Sn²⁺, in which R* is C₁ -C₈ alkyl and q is 2 or 3 and r is 1 or 2, the quotient q/r being 1, 1.5, 2 or 3, and L is a group of the formula II, in which R₁ is hydrogen or methyl and Z₁ is hydrogen, C₁ -C₈ alkyl, C₃ -C₄ alkenyl, C₃ alkynyl, C₂ -C₁₀ alkoxyalkyl, C₇ -C₈ aralkyl, acetyl or one of the groups --CH₂ COOR₂ or --CH₂ --CH(R₃)--OR₄, or a --(CH₂)₄ --R₅, --CH₂ --CH═CH--CH₂ --R₅, ##STR61## radical or a group of the formula III, in which R₂ is C₁ -C₄ alkyl, C₃ -C₄ alkenyl, phenyl, C₇ -C₈ aralkyl or cyclohexyl and R₃ is hydrogen or methyl, R₄ is an aliphatic acyl group having 1-12 C atoms and R₅ is a group of the formula IV, in which Z₂ and Z₃ are as defined below and R₁ is hydrogen, and R₆ is a group of the formula V, in which R₉ is hydrogen or methyl, and R₇ and R₈ independently of each other are hydrogen or methyl and a is 0, 1 or 2 and b is 0 or 1 and c is 0 and, if a and/or b differ from 0, is also 1, and X is --O-- and Y is --O-- or ##STR62## in which R₁₀ is hydrogen or methyl or, if a, b and c are 1, R₇ is hydrogen and Y is --O--, also a group --CH₂ --CH₂ --OR₆, in which R₆ is as defined above, and Z₂ is hydrogen, C₂ -C₁₂ aliphatic acyloxy, benzoyloxy which is unsubstituted or monosubstituted or disubstituted by methyl or methoxy, or a C₂ -C₁₂ acylamido group which is unsubstituted or C₁ -C₄ N-alkylsubstituted, or one of the groups --R₁₂, --(CH₂)_(d) --R₁₂, ##STR63## in which d is 2 to 6 and R₁₂ is a group of the formula VII, in which R₁ and Z₁ are as defined above, or Z₂ is also a group of the formula VIII, in which X' is --O-- or ##STR64## in which R₁₄ is hydrogen or C₁ -C₄ alkyl, and R₁₃ is --(CH₂)_(e) or a group ##STR65## in which e is 0 to 8 and R₁₅ and R₁₆ independently of one another are hydrogen, C₁ -C₄ alkyl, allyl, benzyl, cyanomethyl, cyanoethyl or a group --CH₂ COOR₁₇, in which R₁₇ is methyl or ethyl, or Z₂ is a group of the formulae IX, X or XI, in which R₆ and R₇ are as defined above and R₁₈ is hydrogen, R₁₉ is hydrogen, C₁ -C₄ alkyl, allyl or benzyl, R₂₀ is C₁ -C₄ alkyl or a group of the formula V, which is as defined above, and R₂₁ is C₂ -C₆ alkylene, cyclohexylidene or phenylene, or Z₂ is also a group of the formula XIIa ##STR66## in which a, b, c, R₆ and R₇ are as defined above and f is 0 or 1 and X₁ is --O-- or ##STR67## in which R₁₀ * is hydrogen, C₁ -C₁₂ alkyl, cyclohexyl, C₃ -C₁₄ alkoxyalkyl, C₇ -C₈ aralkyl, phenyl which is unsubstituted or monosubstituted or disubstituted by C₁ -C₃ alkyl and/or C₁ -C₈ alkoxy, or, if a, b and c are 1, R₇ is hydrogen and Y is --O--, also a group --CH₂ --CH₂ OR₆, in which R₆ is as defined above and Y₁ is --O-- or ##STR68## in which R₁₀ ** is hydrogen, C₁ -C₈ alkyl or phenyl, or Z₂ is also one of the groups XIII or XIV, in which R₆ is as defined above and R₂₂ and R₂₃ independently of each other are hydrogen, methyl or ethyl, and Z₃ is hydrogen or cyano, or Z₂ and Z₃ together are one of the formulae XV, XVI or XVII, in which R₆ is as defined above and R₂₄ is hydrogen, methyl or ethyl and R₂₅ is hydrogen, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl or a group --CH₂ COOR₂₆ or --CH₂ --CH(R₈)--OR₆, in which R₆ and R₈ are as defined above and R₂₆ is C₁ -C₁₂ alkyl, and m is 0, 1 or 2 and A is H₂ O or an amine of the formula XVIII, in which R₂₇ is unsubstituted or --OH-substituted C₁ -C₁₈ alkyl, C₅ -C₁₂ cycloalkyl, unsubstituted or C₁ -C₁₂ alkyl-substituted C₆ -C₁₀ aryl or C₇ -C₂₀ aralkyl, a substituted or unsubstituted aminoalkyl group having 1-8 C atoms in the alkyl moiety, or a piperidinyl group, and R₂₈ is hydrogen or unsubstituted or --OH-substituted C₁ -C₁₈ alkyl, C₅ -C₁₂ cycloalkyl or a substituted or unsubstituted aminoalkyl group having 1-8 C atoms in the alkyl moiety, or a piperidinyl group, or R₂₇ and R₂₈ together with the N atom form a pyrrolidine, piperidine or morpholine ring which is substituted by alkyl groups or is unsubstituted, and R₂₉ is hydrogen or unsubstituted or --OH-substituted C₁ -C₁₈ alkyl.
 3. A compound according to claim 1 of the formula I, wherein M^(q)⊕ is Ca²⁺, Mg²⁺, Zn²⁺, Co²⁺, Ni²⁺ or Al³⁺ and 2 is 2 or 3 and r is 1 or 2, the quotient q/r being 1, 1.5, 2 or 3, and L is a group of the formula II, in which R₁ is hydrogen or methyl and Z₁ is hydrogen, C₁ -C₄ alkyl, allyl, C₂ -C₆ alkoxyalkyl, benzyl, acetyl or one of the groups --CH₂ COOR₂ or --CH₂ --CH(R₃)--OR₄ or a group of the formula III, in which R₂ is C₁ -C₄ alkyl and R₃ is hydrogen and R₄ is an aliphatic acyl group having 1-8 C atoms and R₆ is a group of the formula V, in which R₉ is hydrogen, and R₇ is hydrogen and R₈ is hydrogen or methyl and a is 0, 1 or 2 and b is 0 or 1 and c is 0 or, if a and/or b differ from 0, is also 1, and X is --O-- and Y is --O-- or ##STR69## in which R₁₀ is hydrogen or methyl or, if a, b, and c are 1 and Y is --O--, also a group --CH₂ --CH₂ --OR₆, in which R₆ is as defined above, and Z₂ is hydrogen, C₂ -C₇ aliphatic acyloxy, benzoyloxy which is unsubstituted or monosubstituted by methyl or methoxy, or a C₂ -C₇ acylamido group which is unsubstituted or N-substituted by methyl, or one of the groups --(CH₂)_(d) --R₁₂, ##STR70## in which d is 2 to 6 and R₁₂ is a group of the formula VII, in which R₁ and Z₁ are as defined above, or Z₂ is also a group of the formula VIII, in which X' is --O-- or ##STR71## in which R₁₄ is hydrogen or methyl, and R₁₃ is --(CH₂)_(e) -- or a group ##STR72## in which e is 0 to 8 and R₁₅ and R₁₆ independently of each other are hydrogen, C₁ -C₄ alkyl, allyl, benzyl or cyanomethyl, or Z₂ is also a group of the formula XI, in which R₂₀ is a group of the formula V, which is as defined above, and R₂₁ is C₂ -C₆ alkylene or phenylene, or Z₂ is also a group of the formula XIIa, in which a, b, c, R₆ and R₈ are as defined above and f is 0 or 1 and X₁ is --O-- or ##STR73## in which R₁₀ * is hydrogen, C₁ -C₈ alkyl, cyclohexyl, C₃ -C₈ alkoxyalkyl, C₇ -C₈ aralkyl, phenyl which is unsubstituted or monosubstituted by C₁ -C₃ alkyl and/or C₁ -C₂ alkoxy, or, if a, b and c are 1 and Y₁ is --O--, also a group --CH₂ --CH₂ --OR₆, in which R₆ is as defined above, R₁₁ is hydrogen or methyl, and Y₁ is --O-- or ##STR74## in which R₁₀ ** is hydrogen, C₁ -C₄ alkyl or phenyl, or Z₂ is also one of the groups XIII or XIV, in which R₆ is as defined above and R₂₂ and R₂₃ independently of each other are hydrogen, methyl or ethyl, and Z₃ is hydrogen, or Z₂ and Z₃ together are one of the formulae XV, XVI or XVII, in which R₆ is as defined above and R₂₄ is hydrogen or methyl and R₂₅ is C₁ -C₈ alkyl, allyl or one of the groups --CH₂ --COOR₂₆ or --CH₂ --CH(R₈)--OR₆, in which R₆ and R₈ are as defined above, and R₂₆ is C₁ -C₈ alkyl, and m is 0, 1 or 2, and A is H₂ O or an amine of the formula XVIII, in which R₂₇ and R₂₈ independently of each other are C₁ - C₈ alkyl, C₁ -C₆ hydroxyalkyl or a substituted aminoalkyl group of the formula VIIb ##STR75## in which R₁, R₁₁ and R₁₄ are as defined above and v is 1 to 8, or R₂₇ and R₂₈ together with the N atom form a piperidine group, and R₂₉ is hydrogen, C₁ -C₈ alkyl or C₁ -C₆ hydroxyalkyl.
 4. A compound according to claim 1 of the formula I, wherein M^(q)⊕ is Ca²⁺, Mg²⁺, Zn²⁺, Co²⁺, Ni²⁺ or Al³⁺ and q is 2 or 3 and r is 1 or 2, the quotient q/r being 1, 1.5, 2 or 3, and L is a group of the formula II, in which R₁ is hydrogen and Z₁ is hydrogen, methyl, acetyl or a group of the formula III, in which R₆ is a group of the formula V, in which R₉ is hydrogen, and R₇ is hydrogen and R₈ is hydrogen or methyl, and a is 0, 1 or 2 and b is 0 or 1 and c is 0 or, if a and/or b differ from 0, is also 1, X is --O-- and Y is ##STR76## in which R₁₀ is hydrogen, and Z₂ is hydrogen, C₂ -C₇ aliphatic acyloxy, benzoyloxy, an acylamido group which is unsubstituted or N-substituted by methyl, or one of the groups --(CH₂)_(d) --R₁₂, ##STR77## in which d is 2 to 6 and R₁₂ is a group of the formula VII, in which R₁ and Z₁ are as defined above, or Z₂ is also a group of the formula VIII, in which X' is --O-- or ##STR78## in which R₁₄ is hydrogen or methyl, and R₁₃ is --(CH₂)_(e) -- or a group ##STR79## in which e is 0 to 8 and R₁₅ and R₁₆ independently of each other are hydrogen, C₁ -C₄ alkyl, allyl or benzyl, or Z₂ is also a group of the formula XI, in which R₂₀ is a group of the formula V, which is as defined above, and R₂₁ is C₂ -C₆ alkylene, or Z₂ is also a group of the formula XIIa, in which a, b, c, R₆ and R₈ are as defined above and f is 0 or 1 and X₁ is --O-- or ##STR80## in which R₁₀ * is hydrogen, C₁ -C₈ alkyl, C₃ -C₆ alkoxyalkyl, C₇ -C₈ aralkyl, phenyl which is unsubstituted or monosubstituted by methyl, methoxy or ethoxy, R₁₁ is hydrogen or methyl, and Y₁ is --O--, or Z₂ is also one of the groups XIII or XIV, in which R₆ is as defined above and R₂₂ and R₂₃ independently of each other are hydrogen or methyl, and Z₃ is hydrogen, or Z₂ and Z₃ together are one of the formulae XV, XVI or XVII, in which R₆ is as defined above and R₂₄ is hydrogen and R₂₅ is C₁ -C₈ alkyl or one of the groups --CH₂ COOR₂₆ or --CH₂ --CH(R₈)--OR₆, in which R₆ and R₈ are as defined above, and R₂₆ is C₁ -C₄ alkyl, and m is a number 0, 1 or 2, and A is H₂ O or an amine of the formula XVIII, in which R₂₇ and R₂₈ independently of each other are C₁ -C₈ alkyl, C₁ -C₆ hydroxyalkyl or a group VIIb, in which R₁, R₁₁ and R₁₄ are as defined and v is 1 to 8, or R₂₇ and R₂₈ together with the N atom form a piperidine group, and R₂₉ is hydrogen, C₁ -C₈ alkyl or C₁ -C₆ hydroxyalkyl.
 5. A compound of the formula I according to claim 1, wherein m is
 0. 6. The 2:1 Ni-chelate of the 1-[2',1",3"-dioxobutoxy)-ethyl]-2,2,6,6-tetramethylpiperidine enol.
 7. The 1:2 Ni-chelate of the 1,2,6,6-pentamethyl-4-(1',3'-dioxobutoxy)-piperidine enol.
 8. The 1:2 Ni-chelate of the 1,2,6,6-pentamethyl-4-[N-n-heptylamino-N-(1',3'-dioxobutyl)]-piperidine enol.
 9. The 1:2 Ni-chelate of the 2,2,6,6-tetramethyl-4-[N-ethylamino-N-(1',3'-dioxobutyl)]-piperidine enol.
 10. A polymeric material containing a compound of the formula I according to claim
 1. 